Recoilless gun with reverse gas flow



c w. MUS SER 2,924,149

RBCOILLESS GUN WITH REVERSE GAS FLOW- Filed Oct. 7, 1957 20 2| I9 I! I8 I6 I2 I5 I? I0 FIG.|.

FIG. 3.

INVENTOR. C WALTON MUSSER BY wi zm fl-w RECOILLESS GUN WITH REVERSE GAS FLOW C Walton Musser, Beverly, Mass., assignor to the United States of America as represented by the Secretary of the Army Application October 7, 1957, Serial No. 688,794

1 Claim. (Cl. 89-1.7)

(Granted under Title 35, US. Code (1952), sec. 266) The invention described herein may be manufactured and used by or for the Government for governmental purposes without the payment of any royalty thereon.

This invention relates to recoilless guns, and has for its principal object the provision of an improved arrangement of parts and method of operation whereby a more nearly complete burning of the propellant is eflected.

As applied to guns having a gas chamber with a central orifice venturi, the gun of the present invention differs from those of the prior art in that it avoids an excessive efllux of the propellant from the venturi without a considerable increase in the volume of the chamber. As hereinafter explained, this highly desirable result is achieved by an improved arrangement wherein the gases generated by the firing of the projectile are initially made to travel in one direction and are thereafter forced to reverse their direction of travel. Obviously, this longer travel of the gases and more complete burning of the propellant results in a more efficient gun.

The invention will be better understood from the following description when considered in connection with the accompanying drawings and its scope is indicated by the appended claim.

Referring to the drawings:

Fig. 1 is a sectional view of a gun constructed in accordance with the present invention,

Fig. 2 is a sectional view of one form of the forward support for the projectile, and

Fig. 3 is a detail of the support in Fig. 1.

The gun of Fig. 1 includes a barrel 10 and a gas chamber 11 which is provided with a venturi orifice at its rear end. Extending from the nozzle into the chamber is a support 12. This support is provided with open ings 13 which are arranged to admit gas to the barrel 10 when the projectile main body of 14 is in its illustrated rest position. Alternatively, the openings between the chamber 11 and the barrel 10 may be in the form of slots 15 as indicated by Fig. 2. In either case the support is anchored to the casing of the chamber 11 by an anchoring member 16 of a form to afiord ready flow of the gases therethrough.

The projectile 14 is generally of a type well known to those skilled in the art in that it includes a generally conical nose 17, an adapter 18, a boom 19, fins 20 and a charge 21 adapted to be fired by an electric primer (not shown) which is connected to a lead 24. The projectile 14 difiers from those of the prior art in that a body 22 of frangible material, such as sintered sand, is afiixed to its fins in a manner to close the throat of the venturi orifice in the chamber 11.

During the ignition phases in the operation of the gun described above, the powder gases start streaming for- Wardly out of the openings 13 into the barrel 10. At

States Patent the same time, the projectile starts to move forward and the mass of sintered sand starts to move rearwardly out or the throat of the venturi, the openings through which the gases pass and the mass of the sintered sand going through the venturi being so proportioned that the venturi is substantially opened at the instant that projectile closes the openings 13 (or the openings 15 of Fig. 2).

When the projectile has moved far enough to close the openings 13, the flow of the gases in a forward direction is stopped. The powder particles are then masses in the forepart of the chamber and their flow is reversed resulting in prolonged time of travel to the venturi. Since the burning time of powder is measured in mi1liseconds this reversal of the propellant enables it to burn more completely and results in a smaller effiux of the propellant without increasing the volume of the chamber. As a result, the gun is more efficient since even a small decrease in the percentage of the propellant ejected through the venturi increases the energy within the gun.

After the projectile has passed the orifices 13 or 15, the gases cannot flow ahead of the projectile but they can flow through the bore of the gun and also around through the openings in the support 12, thereby lessening the resistance to the flow of gases into the region of the projectile.

While the gun has been shown as having a smooth bore, it is to be understood that the barrel 10 may be rifled and that projectile may be provided with a rotating band without departing from the spirit and scope of the present invention.

I claim:

The combination with a recoilless gun, of a projectile therefor including a generally conical nose at its fore end, a main body portion to which said nose is affixed, an axial boom extending rearwardly of the main body of the projectile, stabilizing fins aflixed to a rear portion of said boom, an adapter between said boom and the main body of said projectile, a propelling charge around said boom between said fins and said adapter, means for firing said charge, and a mass of frangible sintered sand aflixed to said fins, said gun having a barrel, a gas chamber around said projectile anud forming a venturi orifice in rear thereof initially substantially closed by said mass of sintered sand, said chamber having an outer wall secured the gun barrel, a tubular support for the main body of said projectile, a perforate anchoring member between a rear portion of said tubular support and an outer wall of said chamber, said tubular support being perforate radially outside of said conical nose portion of said projectile and in advance of the main body portion of the projectile, whereby on ignition of said propelling charge gas at first moves forwardly through the perforate portion of said tubular support and then after breakage of the frangible sintered sand moves rearwardly out of the venturi orifice giving the propellant a longer burning time.

References Cited in the file of this patent UNITED STATES PATENTS 1,380,358 Cooke June 7, 1921 1,469,918 De Maine Oct. 9, 1923 2,210,959 Storm Aug. 13, 1940 2,383,053 Fanger et al Aug. 21, 1945 FOREIGN PATENTS 300,428 Italy Sept. 8, 1932 

